Burnham heat boiler

Question

i have Burnham heat boiler and last year we installed honeywell aquastat L8148E but did not get to use heat (it was end of march) this year when we start the heat but there was no heat i checked the circulator and found it seized and replaced with new one now when i first start the boiler cold it fires the boiler and after 5 minutes turn off the boiler and circulator stays running and boiler will not come on, no 24v volts at aquastat to gas valve this is fixed aquastat, what you think the problem looks like. i bleed the water good 10 minutes after replacing the circulator. no zone valve just feed and return, i installed the circulator arrow toward down to boiler on return, i bled the system before circulator on return there is the valve. there is another valve after the circulator which i did not bleed. any thoughts